Were getting a "BadAuthentication" exception with on of our accounts when calling the AuthToken.getAuthToken() method but the authentication were using looks correct.
"Exception message: Auth token could not be retrieved because of error: BadAuthentication"
My best guess is the question is about AdWords API. Please learn that the API guys have a separate forum and are more likely to give you an authentic answer in their own community which is linked-to below. You are advise to re-post your query there.
AdWords API Forum
Thanks for your understanding.